Kun Shan Chun, an FBI employee who pleaded guilty in federal court to having acted as an agent of the Chinese government, is pictured in New York on Monday. Mr. Chun, who was born in China and worked at the FBI for 19 years, is accused of having disclosed 'sensitive' information to Chinese associates.

“Americans who act as unauthorized foreign agents commit a federal offense that betrays our nation and threatens our security,” said Preet Bharara, the US attorney for the southern district of New York, in a statement. “And when the perpetrator is an FBI employee, like Kun Shan Chun, the threat is all the more serious and the betrayal all the more duplicitous.”

Chun was also accused of lying about his relationship with Chinese associates and a firm called the Zhuhai Kolion Technology Company. On Monday, he pleaded guilty to a single count of acting in the United States as an agent of China, The New York Times reports.

“At the time I knew what I was doing was wrong, and I am sorry for my actions,” Chun said in court.

The case comes in the wake of espionage charges filed against Edward Lin, a naval flight officer who is now facing a court martial. Prosecutors have accused Mr. Lin, who is originally from Taiwan, of attempting to pass secret information to at least one foreign agent, an undercover FBI agent fluent in Mandarin, USNI News reports.

But attorneys for Lin, who became a US citizen in 1998, maintained that the FBI entrapped him into providing the informant with publicly available information and that he was improperly advised of his rights when detained in Hawaii in September 2015. He has pleaded not guilty, according to USNI News.

The guilty plea from "Joey" Chun, who was arrested by the FBI in March following an undercover operation, comes a year after FBI officials noted a 53 percent increase in economic espionage cases aimed at US companies, with many of the perpetrators coming from China.

Chun's case unfolded over several years. He began working at the FBI as an electronics technician and was granted a top secret security clearance in 1998.

While on a trip to Europe in 2011, Chun met with a Chinese official who asked him about his work at the FBI. Over the course of subsequent meetings, Chun discussed sensitive information with the official, including disclosing the identity of an FBI Special Agent, the government charged.

In 2013, Chun sent the official a copy of the FBI organizational chart with personnel names removed.

Two years later, he sent the official photos of documents from the FBI’s New York office that summarized surveillance technologies used by the FBI, according to the Justice Department.

The government said that since at least 2006, Chun and some relatives had relationships with Chinese nationals purporting to be affiliated with Kolion, the technology firm, who asked him to carry out research and consulting tasks in the US.

In February 2015, Chun told an undercover FBI agent that Kolion had “government backing.” Prosecutors also said Chun repeatedly attempted to hide his relationships with the Chinese official and other Chinese nationals by lying on required disclosure forms.

Emil J. Bove III, a prosecutor, said in court Monday that Chun had said that he was “motivated in part by financial benefit,” the Times reports.

While the maximum sentence is 10 years, the government and the defense agreed that a sentence of 21 to 27 months is appropriate under federal sentencing guidelines, the paper reports.

Jonathan Marvinny, Chun’s federal public defender, said his client had “accepted responsibility for some mistakes in judgment that he deeply regrets. The truth is that Mr. Chun loves the United States and never intended to cause it any harm.”